In a large bowl, combine kimchi, scallions, 1 cup chopped watercress, pork, garlic, cayenne, flour, egg, and 6 tablespoons water. Stir to combine.
Meanwhile, heat 2 tablespoons oil in a large nonstick skillet over medium-high heat. Add half of pancake mixture, pat it into a large pancake, and cook until browned on the underside, about 4 minutes. Slide the pancake onto a plate, then carefully flip it back into the skillet to brown the other side, about 4 minutes. Repeat with remaining pancake mixture and oil. Transfer both pancakes to a cutting board to cut each cake into 4 wedges.
While pancake cooks, whisk together soy sauce, vinegar and sesame oil. In a small bowl, toss remaining 1/2 cup watercress and radish together with salt and pepper. Serve wedges of pancake topped with watercress relish; spoon sauce over top or serve alongside.
Before her diagnosis, Caroline wrote a book on cakes called Cake Magic!. She started developing a birthday cake using her gluten-free mix found in that book. Check out other recipes she’s developing for her new life—and the stories behind them—on her blog, The Wright Recipes. Her next book, Catalan Food, written with chef Daniel Olivella, comes out in early September from Clarkson Potter.